The spring pressed jaw animal traps have been in use since before 1900 and over the years have remained generally the same. They embody a pair of generally U-shaped jaws of strong construction with the leg portions of the jaws having tip portions turned outwardly endwise in the jaw planes to provide pintles that are seated in spaced apart holes in upturned end portions of a base plate that also supports the pan and the latch by which one of the jaws is held open.
A novelty search of the prior patents disclosed U.S. Pat. No. 716,255 to Leonard using the structure just described wherein the jaws are closed by a single leaf spring of V-shape. Also in U.S. Pat. No. 1,337,149 to Nelson and Boode, a similar trap is shown embodying two V-shaped springs for lifting the jaws. These springs have holes in both ends and the metal around the holes is cupped so that greater leverage may be had at the beginning of the lift of the jaws by the springs. Another kind of jaw lifting spring is provided with a flaring shape 10 around the jaw opening 11 in the U.S. Pat. No. 1,430,242 to Mullen.
The U.S. Pat. No. 2,333,828 uses coiled spring means to lift the jaws and the jaw engaging tubes 47 are flat topped to support the jaws in open position.
In all of these spring closed leg catching jaw traps, it has been a problem to so construct the trap as to securely hold the leg of the animal and not break or cut off the leg. Padding of the jaws with resilient leg engaging pads is disclosed in the U.S. Patent to Briddell, No. 2,146,464, also in the Maddox U.S. Pat. No. 1,825,193 and the O'Neil U.S. Pat. No. 2,316,970. In these patents as in all of the patents discussed herein, the leg engaging faces of the jaws are flat with corners at both edges of the flat face. Such a jaw face is apt to lead to chewing by the animal at these corners. If the face is a rubber or other yielding material, the material and the leg is chewed off at the corner and a crippled animal is returned to the wild.